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Food production and pharmaceutical synthesis are posited as essential biotechnologies for facilitating human exploration beyond Earth. These technologies not only offer critical green space and food agency to astronauts but also promise to minimize mass and volume requirements through scalable, modular agriculture within closed-loop systems, offering an advantage over traditional bring-along strategies. Despite these benefits, the prevalent model for evaluating such systems exhibits significant limitations. It lacks comprehensive inventory and mass balance analyses for crop cultivation and life support, and fails to consider the complexities introduced by cultivating multiple crop varieties, which is crucial for enhancing food diversity and nutritional value. Here we expand space agriculture modeling to account for nitrogen dependence across an array of crops and demonstrate our model with experimental fitting of parameters. By adding nitrogen limitations, an extended model can account for potential interruptions in feedstock supply. Furthermore, sensitivity analysis was used to distill key consequential parameters that may be the focus of future experimental efforts.

People frequently encounter the challenge of deciding when to stop exploring options to optimize outcomes, such as when selecting an apartment in a fluctuating housing market or booking a dinner reservation on New Year's Eve. Despite experiencing these decisions on multiple occasions, people often struggle to stop searching optimally. This research investigates human learning abilities in optimal stopping tasks, focusing on feedback and knowledge of option value distributions. Through an experimental sequential choice task, we demonstrate that experience improves performance, with feedback significantly influencing learning. We also find that awareness of the value distribution reduces the duration of the search. A cognitive model accurately predicts these effects, shedding light on human learning processes.

Abstract Food production and pharmaceutical synthesis are posited as essential biotechnologies for facilitating human exploration beyond Earth. These technologies not only offer critical green space and food agency to astronauts but also promise to minimize mass and volume requirements through scalable, modular agriculture within closed-loop systems, offering an advantage over traditional bring-along strategies. Despite these benefits, the prevalent model for evaluating such systems exhibits significant limitations. It lacks comprehensive inventory and mass balance analyses for crop cultivation and life support, and fails to consider the complexities introduced by cultivating multiple crop varieties, which is crucial for enhancing food diversity and nutritional value. Here we expand space agriculture modeling to account for nitrogen dependence across an array of crops and demonstrate our model with experimental fitting of parameters. By adding nitrogen limitations, an extended model can account for potential interruptions in feedstock supply. Furthermore, sensitivity analysis was used to distill key consequential parameters that may be the focus of future experimental efforts.

Background: Large osteochondral lesions of the humeral head can result from locked posterior dislocations, avascular necrosis, and osteochondritis dissecans. Fresh osteochondral allograft (OCA) transplantation is a treatment option for young patients with focal osteochondral defects of the humeral head. The purpose of this case series was to assess graft survivorship, subjective patient-reported outcomes, and satisfaction among 7 patients who underwent OCA transplantation of the humeral head. Methods: We identified 7 patients who underwent humeral head OCA transplantation between 2008 and 2017. A custom questionnaire including the American Shoulder and Elbow Surgeons score, Quick Disabilities of the Arm, Shoulder, and Hand score (QuickDash), Likert satisfaction, and reoperations was mailed to each patient. Clinical failure was defined as further surgery that involved removal of the allograft. Results: Median follow-up duration was 10 years (range, 4.6 to 13.5 years) with a median age of 21.6 years (range, 18.5 to 43.5 years). Most patients (86%) reported improved function and reduced pain. At the final follow-up, 71% of patients reported ongoing problems with their shoulder including pain, stiffness, clicking/grinding, limited range of motion, and instability. Return to recreational activities was high at 86% but 43% expressed limitations with activity due to their shoulder. Overall satisfaction was high at 71% with mean American Shoulder and Elbow Surgeons and QuickDASH scores at 62.4 and 29.2, respectively. Reoperation after OCA occurred in 1 patient (14%). Conclusion: Among this case series of 7 patients who underwent OCA transplantation of the humeral head, patient satisfaction was high at 10-year follow-up and most returned to recreational activity although most also had persistent shoulder symptoms.

Health equity research has identified fundamental social causes of health, many of which disproportionately affect Black Americans, such as early life socioeconomic conditions, neighborhood disadvantage, and racial discrimination. However, the role of life course factors in premature mortality among Black Americans has not been tested extensively in prospective samples into later adulthood. To better understand how social factors at various life stages impact mortality, this study examines the effect of life course poverty, neighborhood disadvantage, and discrimination on mortality and factors that may buffer their effect (i.e., education, social integration) among the Woodlawn cohort (N = 1242), a community cohort of urban Black Americans followed since 1966. Taking a life course perspective, we analyze mortality data for deaths through age 58 years old, as well as data collected at ages 6, 16, 32, and 42. At age 58, 204 (16.4%) of the original cohort have died, with ages of death ranging from 9 to 58.98 (mean = 42.9). Cox proportional hazard models adjusting for confounders show statistically significant differences in mortality risk based on timing and persistence of poverty; those who were never poor or poor only in early life had lower mortality risk at ages 43-58 than those who were persistently poor from childhood to adulthood. Education beyond high school and high social integration were shown to reduce the risk of mortality more for those who did not experience poverty early in their life course. Findings have implications for the timing and content of mortality prevention efforts that span the full life course.

Here we review the 400-year history of hydroponic culture and describe a unique management approach that does not require leaching or discarding solution between harvests. Nutrients are maintained at a low and steady concentration by daily additions of a dilute solution that replaces the transpired water along with the nutrients that were removed in growth each day. A stable pH and a low steady-state concentration of ammonium are maintained through automated additions of a solution of nitric acid and ammonium nitrate. Ample solution volume (at least 20 cm deep) stabilizes nutrient concentrations, reduces root density, and improves uniformity. Gentle aeration at ≈100 mL·min−1·L−1 maintains dissolved oxygen near saturation and increases uniformity throughout the rhizosphere. These practices facilitate a uniform, closed, root zone with rigorous pH control that provides the micromolar nutrient concentrations of N and P that are representative of field soils.

Temporal separation of red (R) and blue (B) (alternating R/B) photons has been reported to increase leaf area, photon capture, and yield of lettuce compared with delivering both colors together (concurrent R+B). We grew three diverse lettuce cultivars (Grand Rapids, Rex, and Red Sails) under concurrent R+B photons (9/1 ratio) and alternating R/B photons (9/1 ratio) under an equal daily light integral (DLI) of either 8.6 or 23 mol⋅m−2⋅d−1. Contrary to five previous studies, we found no increase in either leaf area or fresh mass and dry mass in any of the alternating R/B photon treatments compared with concurrent R+B photons. In fact, at a DLI at 8.6 mol⋅m−2⋅d−1, alternating R/B photons decreased the dry mass of ‘Grand Rapids’ and ‘Rex’ lettuce by 38% and 17%, respectively. Two previous studies reported that photosynthetic rates increased with alternating R/B photons; however, we found that the net assimilation rate was generally decreased by alternating R/B photons. An analysis of images obtained from automated digital photography revealed that the relative expansion rate of leaves was 61% higher during intervals of pure B rather than intervals of pure R photons at the same photosynthetic photon flux density; however, this did not result in a higher leaf area compared with concurrent R+B photons. Overall, our studies do not indicate that alternating R/B photons increase lettuce leaf area or yield compared with concurrent R+B photons.

John C Grable,1,* Kevin Shan,1,* Matthew Wang,1,* Daniel D Han,1,* Kristen Sportiello,1,* Melissa Chang,1,* Justin R Sysol,1,* Doris Bugbee,2,* Kenneth Peltzer1,* 1Department of Medicine, University of Rochester School of Medicine, Rochester, NY, USA; 2Department of Nursing, University of Rochester School of Medicine, Rochester, NY, USA*These authors contributed equally to this workCorrespondence: John C Grable, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY, 14642, USA, Tel +1 585-275-7424, Fax +1 585-276-2820, Email john_grable@urmc.rochester.eduPurpose: Providing effective tobacco dependence treatments to hospitalized patients remains a challenge. Prior to 2021, the Rochester Model program used staff nurses for both bedside and post-discharge counseling necessary to maintain abstinence. When nurse shortages and elevated job stress occurred during the COVID Pandemic, we proposed that medical students learn to counsel patients at the bedside and after discharge.Patients and Methods: Due to COVID restrictions, first- and second-year medical students trained using remote Zoom sessions. The total training time was 2.5 hr without role-play or additional evaluations. A survey measured the students’ satisfaction, confidence, and counseling barriers. A smoking patient on a participating hospital unit can enroll in the program. Students delivered bedside counseling, then provided follow-up treatment and outcome calls along with New York State Quitline counselors.Results: The survey demonstrated that 89% of the students were satisfied with the training. The bedside counseling confidence was greater than the phone counseling confidence. All students felt the program experience has value to them as future physicians. 124 smoking patients enrolled, and outcomes followed out to 6 months. The 7-day point prevalence quit rates using the as-treated (patients contacted) analysis were 57% at 4 weeks, 48% at 3 months, and 43% at 6 months. The 7-day point prevalence quit rates using the intent-to-treat (all patients) analysis were 31% at 4 weeks, 16% at 3 months and 14% at 6 months.Conclusion: Medical students given minimal training are effective tobacco cessation counselors at no cost to the hospital system. The Rochester Model program using student counseling benefits patients, the students, and the health-care system.Plain Language Summary: Hospitalization is an opportunity to help smokers quit. Successful programs require both bedside counseling and post-discharge contacts beyond a month. Cost remains the major issue for treating hospitalized smokers. Prior to the COVID Pandemic, the Rochester Model program used hospital nurses as bedside, post-discharge call counselors and champions. However, during the Pandemic, nurse shortages and work stress reduced their participation. Medical students seeking early patient contact trained as counselors, and the program shows promising quit rates at no cost. The Rochester Model supports the real-world application of medical students in hospital tobacco treatment programs.Keywords: tobacco dependence treatment, medical students, nurse counseling, quit-line counseling

Rhizosphere pH determines nutrient bioavailability, but this pH is difficult to measure. Standard pH tests require adding water to growth media. This dilutes hydrogen ion activity and increases pH. We used a novel, in situ, pointed-tip electrode to estimate rhizosphere pH without dilution. Measurements from this electrode matched a research-grade pH meter in hydroponic nutrient solutions. We then compared measurements from this electrode to saturated paste and pour-through methods in peat moss, coconut coir, and pine bark. The pointed-tip electrode was unable to accurately measure pH in the highly-porous pine bark media. Adding deionized water to the other media at container capacity using the saturated paste method resulted in a pH that was 0.59 ± 0.30 units higher than the initial in situ measurement at the top of the container. This increase aligns with established solution chemistry principles. Measurements of pH using the pour-through method were 0.38 ± 0.24 pH units higher than in situ measurements at the bottom of the container. We conclude that in situ pH measurements are not subject to dilution and are thus more representative of the rhizosphere pH than the saturated paste and pour-through techniques.

Many models in Cognitive Science require data to calibrate parameters. Some modelers calibrate their models’ parameters for each individual in a data set, and others work at the aggregate level. Generally, the accuracy of a model is judged by the degree to which human data are replicated, and the model parameters are interpreted accordingly. It is not too surprising that models that are developed for a particular task and fit to each individual’s data in such a task replicate the human data well. The question is, however, whether those models can make predictions in the absence of human data. In this paper, we present a theory-driven model of a well-known sequential decision task (the Balloon Analog Risk Task, BART) which is able to make predictions in the absence of human data. The cognitive model is grounded on the processes and mechanisms of Instance-Based Learning (IBL) Theory of experiential choice. We demonstrate the simulation predictions from an IBL model and those of a well-known model of the BART, which depends on the fits to human data. We further show that when making predictions without data, the IBL model provides predictions that are both theoretically founded and accurate, while the Two-Parameter model performs much worse than when fit to data. We conclude with a discussion of the benefits of making theory-based predictions in the absence of human data for our community.

Background: The purpose of this study was to evaluate whether there were differences in patient-reported outcomes, operative times, satisfaction scores, and complications between patients undergoing total hip arthroplasty (THA) performed through a direct anterior approach on a specialized traction table or a regular operating room table. Methods: Patients who underwent a direct anterior approach THA on a specialized table or a regular table with a minimum 1-year follow-up were included. Patient-reported outcome measures and THA satisfaction were recorded. Demographics, complications, and operative times (both in-room and surgical time) were evaluated. Three hundred twenty-two patients were included with 217 (67.4%) undergoing anterior THA on the specialized table and 105 (32.6%) on a regular table. Results: Outcome measures were similar at 4 months and 1 year postoperatively. Average operative time was 87 minutes (range, 50-160) and 90 minutes (range, 35-197) for the specialized table and regular table groups (P = .314). Average total in room time was 123 minutes (range, 87-201) and 120 minutes (range, 62-255) for the specialized table and regular table groups (P = .564). Satisfaction rates between groups did not differ (P = .564). No differences were found in complication rates at 4 months (P = .814) or 1 year (P = .547). Conclusions: This study shows that the direct anterior approach for THA can be safely and efficiently performed on either a specialized traction table or a regular table. Surgeons should continue to utilize the approach and set-up they are most comfortable with to achieve an optimal outcome for the patient.

John C Grable,1,* Jonathan K Lin,2,* Kenneth Peltzer,1,* Rebecca Schultz,1,* Doris Bugbee,3,* Mikhail Pilipenko,3,* Scott C Levy,1,* Shayne Hawkins3,* 1Department of Medicine, University of Rochester School of Medicine, Rochester, NY, USA; 2Department of Medicine, UT Southwestern Medical Center, Dallas, TX, USA; 3Department of Nursing, University of Rochester School of Medicine, Rochester, NY, USA*These authors contributed equally to this workCorrespondence: John C Grable, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY, 14642, USA, Tel +1 585-275-7424, Fax +1 585-276-2820, Email john_grable@urmc.rochester.eduPurpose: Delivering evidence-based tobacco dependence treatments to hospital patients in real-world settings continues to be a challenge. To achieve long-term abstinence, a program should provide both bedside counseling and post-discharge contacts. These program features are necessary but difficult to implement due to lack of training, time and low administrative support. The Rochester Model is a tobacco treatment program using existing staff and medical students to reduce the barriers for treating hospitalized smokers.Patients and Methods: Any smoking patient admitted to a participating hospital unit can participate. Staff nurses, mid-level providers and physicians deliver the counseling steps during the admission. Nurses hold two bedside counseling sessions, while providers give quitting advice and encourage pharmacotherapy. Nurses also contribute as unit champions and post-discharge call counselors. New York State quit line counselors combined with a University of Rochester call team fulfill the post-discharge calls. The latter call team is composed of staff nurses, respiratory therapists and medical students.Results: The number of smoking patients screened was 2610 while 385 enrolled after a proof-of-concept period. The 7-day point prevalence quit rates using the as treated (patients contacted) analysis is 50% at 4 weeks, 42% at 3 months and 38% at 6 months. The 7-day point prevalence quit rates using the intent-to-treat (all patients) analysis is 23% at 4 weeks, 16% at 3 months and 14% at 6 months.Conclusion: Preliminary data on the Rochester Model is showing an effective yet affordable tobacco treatment program using hospital staff and medical students. Nurses serve as bedside counselors, unit champions and post-discharge call counselors. Hospitals, even with limited resources, can implement tobacco treatment programs using existing staff.Keywords: tobacco dependence treatment, nurse counseling, quit-line counseling, respiratory therapists, medical students

Copper (Cu) is typically adequate at 0.5 μM (0.03 ppm) in hydroponics and at 2 μM (0.125 ppm) in soilless media, but elevated levels can be used to inhibit pathogenic fungal growth. We studied the effect of elevated Cu on the growth of lettuce and tomato in peat-based media and deep-flow hydroponics. Lettuce growth in hydroponics was not hindered until a concentration greater than 4 μM (0.25 ppm) Cu was used, which is eight times greater than the adequate level. Tomato was more tolerant of elevated Cu, with no growth suppression up to 8 μM (0.5 ppm) in hydroponics. Organic matter tightly binds Cu, and bioavailability is thus determined by organic components in soilless media. We confirmed an adsorption capacity of 19 mg Cu per g of peat, which explains why there was no inhibition of lettuce or tomato growth up to 1000 μM (64 ppm) Cu in peat-based media. When chelated with ethylenediaminetetraacetic acid, Cu binding to organic matter was reduced and growth was decreased in lettuce but not tomato. Both species tolerated a 100-fold greater concentration of Cu in peat-based media than in deep-flow hydroponics. Elevated Cu in solution increased concentrations 20 times greater in root tissue than in leaves. These solution and tissue concentrations are greater than identified toxicity thresholds of pathogenic fungal and fungal-like organisms, and could thus be used to suppress root-borne fungal and fungal-like diseases.

A crewed mission to and from Mars may include an exciting array of enabling biotechnologies that leverage inherent mass, power, and volume advantages over traditional abiotic approaches. In this perspective, we articulate the scientific and engineering goals and constraints, along with example systems, that guide the design of a surface biomanufactory. Extending past arguments for exploiting stand-alone elements of biology, we argue for an integrated biomanufacturing plant replete with modules for microbial in situ resource utilization, production, and recycling of food, pharmaceuticals, and biomaterials required for sustaining future intrepid astronauts. We also discuss aspirational technology trends in each of these target areas in the context of human and robotic exploration missions.

Silicon (Si) is a beneficial element that is usually ample in mineral soil solution, but it is minimally bioavailable from soilless substrates. Several Si additives are commercially available, but the rate of dissolution of Si is not well-characterized. The ideal additive would steadily release bioavailable Si over the crop lifecycle. We report the long-term (120 days) dissolution of Si from soilless substrates and substrate additives. Studies involving gently agitated containers with deionized water indicated that perlite, sphagnum peat, vermiculite, and coconut coir released less than 0.03 mmol Si per liter of substrate per day. Rice hulls and wollastonite (CaSiO3) had 7- to 130-times faster rates of dissolution in this system; therefore, they were further studied in peat-based media. Dissolution of Si from the addition of 1 g wollastonite per liter of peat peaked at day 10 at 2.1 mmol Si per liter of media per leaching event (15% by volume); then, it gradually decreased over 120 days. The peak dissolution of Si amended with 12% rice hulls was similar, but it gradually increased over time. The concentrations of nine heavy metals in plant tissue were compared with untreated control plants to determine wollastonite and steel slag. The concentration of some elements statistically increased, but all concentrations were well below the legal concentration limits of these elements for human consumption in the United States. These results indicate that both wollastonite and rice hulls steadily release Si for up to 4 months; therefore, they are good sources of Si for container-grown crops in soilless media.

Ethylene is an essential plant hormone at low concentrations. Concentrations in the field rarely exceed 5 nmol⋅mol−1 (0.005 ppm), but it can accumulate as a gas in closed, indoor environments. These elevated levels can reduce growth and yield. Temperature alters ethylene synthesis and has the potential to influence ethylene sensitivity of crop plants in sealed greenhouses and indoor environments. We studied ethylene sensitivity of tomatoes (Solanum lycopersicum L. cv. MicroTina) using a unique, 12-chamber system. Ethylene levels of 0, 20, and 40 nmol⋅mol−1 (parts per billion) were maintained throughout the life cycle, at an air temperature of 22 or 28 °C. Yield of red fruit was three times higher at 22 than at 28 °C. There was a steady decrease in yield with increasing ethylene concentration, but vegetative growth was reduced less than 10% in any treatment. The highest ethylene concentration reduced yield to 11% of the control at 22 °C and to 4% of the control at 28 °C; the intermediate ethylene level reduced yield to 51% of the control at 22 °C and 37% at 28 °C. Regardless of temperature, filtering of ethylene in indoor environments to below 20 nmol⋅mol−1 is necessary to achieve normal fruit set and yield in tomato.

Abstract Purpose This study aimed to investigate the complications of primary total hip arthroplasty based on immediate postoperative X-rays. The overall quality and cost of X-rays were assessed. Methods The institutional database was queried to identify all patients who underwent total hip arthroplasty in a single institution between January 1, 2018, and December 31, 2018. Immediate postoperative X-rays were reviewed to identify the complications such as periprosthetic fractures, dislocation, and fixation failure. The quality and cost of X-ray were assessed. The complications were categorized as "known" and "unknown" according to the intraoperative fluoroscopic results. Results A total of 518 total hip arthroplasties were included in this study. Based on intraoperative fluoroscopy, periprosthetic fractures were found in 10 (2%) THAs. Compared to the X-rays taken immediately after surgery, 9 periprosthetic fractures (recorded as "known") were found and 1 was not (recorded as "unknown"). There was no significant difference between intraoperative fluoroscopy and X-rays (P > 0.05). Of the 518 X-rays, 225 (43%) were of suboptimal quality. The cost of a single portable pelvic X-ray was $647. Conclusion In total hip arthroplasty, X-rays taken immediately after surgery rarely reveal unknown complications. The X-rays are often of suboptimal quality, have minimal clinical utility, and are less cost-effective.

Ultraviolet photons (UV) can damage critical biochemical processes. Plants synthesize photo-protective pigments that absorb UV to minimize damage. Cannabinoids absorb UV, so increased UV has the potential to increase cannabinoid synthesis. Studies in the 1980’s provided some evidence for this hypothesis in low-cannabinoid cultivars, but recent studies did not find an increase in cannabinoid synthesis with increasing UV in high-cannabinoid cultivars. These studies used low UV photon fluxes, so we examined the effect of higher UV photon fluxes. We used fluorescent UV lights with 55% UV-B (280 to 314 nm) and 45% UV-A (315 to 399 nm). Treatments began three weeks after the start of short days and continued for five weeks until harvest. Established weighting factors were used to calculate the daily biologically effective UV photon flux (UV-PFDBE; 280 to 399 nm). Daily UV-PFDBE levels were 0, 0.02, 0.05, and 0.11 mol m-2 d-1 with a background daily light integral (DLI) of 30 mol m-2 d-1. This provided a ratio of daily UV-PFDBE to DLI of 41 to 218% of summer sunlight in the field. Cannabinoid concentration was 3 to 13% higher than the control in UV treated plants, but the effect was not statistically significant. Fv/Fm and flower yield were reduced only in the highest UV treatment. These data support recent literature and lead us to conclude that an elevated flux of UV photons is not an effective approach to increase cannabinoid concentration in high-cannabinoid cultivars.

N2 fixation is essential to the sustainability and operation of nitrogen systems but is energetically expensive. We developed a model and used sensitivity analysis to identify the impact of aerobic and anaerobic waste digestion, crop harvest index, rates of recovery of recalcitrant N, and the rate of N2 fixation in a system combining nitrogen fixation and recycling. The model indicates that the rate of N2 fixation, loss from reactors, fertilization efficiency, and crop harvest index have the largest impact on maintaining bioavailable N. N recoveries from aerobic and anaerobic digestion, as well as direct-to-soil fertilization, are not well characterized, but the case studies using this model indicate that their efficiencies are critical to N recovery. The findings of this model and its presented case studies can be used as a guide in the design of closed-loop habitats both on Earth and in space. These results reveal a clear need for continued research in the areas of N-efficient digestion, fertilization, and fixation.

IntroductionAutomated plant-based measurements of water stress have the potential to advance precision irrigation in orchard crops. Previous studies have shown correlations between sap flow, line variable differential transform (LVDT) dendrometers and fruit tree drought response. Here we report season-long automated measurement of maximum daily change in trunk diameter using band dendrometers and heated needles to measure a simplified sap flow index (SFI).MethodsMeasurements were made on two apple cultivars that were stressed at 7 to 12 day intervals by withholding irrigation until the average stem water potential (ΨStem) dropped below -1.5 MPa, after which irrigation was restored and the drought cycle repeated.ResultsDendrometer measurements of maximum daily trunk shrinkage (MDS) were highly correlated (r² = 0.85) with pressure chamber measurements of stem water potential. The SFI measurements were less correlated with stem water potential but were highly correlated with evaporative demand (r² = 0.82) as determined by the Penman-Monteith equation (ETr).DiscussionThe high correlation of SFI to ETr suggests that high-density orchards resemble a continuous surface, unlike orchards with widely spaced trees. The correlations of MDS and SFI to ΨStem were higher during the early season than the late season growth. Band dendrometers are less labor intensive to install than LVDT dendrometers and are non-invasive so are well suited to commercialization.

The IL-10/IL-10 receptor (IL-10R) axis plays an important role in attenuating neuroinflammation in animal models of Multiple Sclerosis (MS) and increased IL-10 has been associated with a positive response to MS disease modifying therapy. Because environmental factors play an important role in MS susceptibility and disease course, identification of environmental factors that impact the IL-10/IL-10R axis has therapeutic potential. In this review, we provide historical and updated perspectives of how IL-10R signaling impacts neuroinflammation, discuss environmental factors and intestinal microbes with known impacts on the IL-10/IL-10R axis, and provide a hypothetical model for how B cells, via their production of IL-10, may be important in conveying environmental “information” to the inflamed central nervous system.

Plants compete for sunlight and have evolved to perceive shade through both relative increases in the flux of far-red photons (FR; 700 to 750 nm) and decreases in the flux of all photons (intensity). These two signals interact to control stem elongation and leaf expansion. Although the interacting effects on stem elongation are well quantified, responses for leaf expansion are poorly characterized. Here we report a significant interaction between far-red fraction and total photon flux. Extended photosynthetic photon flux density (ePPFD; 400 to 750 nm) was maintained at three levels (50/100, 200 and 500 µmol m-2 s-1), each with a range of 2 to 33% FR. Increasing FR increased leaf expansion in three cultivars of lettuce at the highest ePPFD but decreased expansion at the lowest ePPFD. This interaction was attributed to differences in biomass partitioning between leaves and stems. Increased FR favored stem elongation and biomass partitioning to stems at low ePPFD and favored leaf expansion at high ePPFD. In cucumber, leaf expansion was increased with increasing percent FR under all ePPFD levels showing minimal interaction. The interactions (and lack thereof) have important implications for horticulture and warrant further study for plant ecology.

Abstract Background The number of total knee arthroplasties (TKA) performed in the United States is projected to rise significantly, with a proportionate increase in the revision burden. Understanding the mechanism of failure in primary TKA is important as etiologies continue to evolve and reasons for revision change. The purpose of this study was to determine the reason for revision TKA at our institution among early and late failures and assess if the etiology has changed over a 10-year time-period. Methods We identified 258 revision TKAs performed at our institution between 2005 and 2014. Reasons for revision TKA were categorized according to diagnosis. We also conducted subgroup analysis for TKA revisions performed within two years of the primary TKA (early failures) and those performed after two years (late failures). Revision TKAs were also grouped by year of primary TKA (before and after 2000) and time period in which the revision TKA was performed (2005–2009 and 2010–2014). Results The most common reason for revision TKA was infection (29.3%), followed by aseptic loosening (19.7%), which together accounted for half of all revisions. Other indications for revision were instability (11.6%), osteolysis (10.4%), arthrofibrosis (8.1%), polyethylene (PE) wear (7.7%), malalignment/malposition (5.4%), patellar complication (3.1%), periprosthetic fracture (2.3%), pain (1.5%), and extensor mechanism deficiency (0.8%). Nearly half of early failures (47%) were due to infection. Osteolysis and PE wear made of a significantly higher proportion of revisions of TKAs performed prior to 2000 compared to index TKAs performed after 2000. Conclusion At our institution, infection was the most common reason for revision TKA. Infection had a higher rate of early revisions. Proportion of TKAs revised for osteolysis and PE wear was higher for TKAs performed prior to 2000. Proportion of revision TKA for infection and instability were higher with TKAs performed after 2000.